FIG. 1.

(A) Hypoxia Hx) induces the immediate-early accumulation of c-jun mRNA independently of the presence of HIF-1α. Autoradiograph of a Northern blot of total RNA from wild-type and HIF-1α null mEFs incubated under aerobic conditions (air [5% CO₂]) or exposed to hypoxia (pO₂ ≤ 1%) for the indicated times. The blot was probed sequentially for c-jun and 28S rRNA transcripts. This finding is representative of three independent experiments. (B) The early hypoxia-inducible accumulation of c-jun mRNA is dependent on serum (10% FBS). Histogram of relative amounts of c-jun mRNA detected by quantitative RT-PCR amplification of total RNA harvested at the indicated times. For details, see Materials and Methods.